Centralized lubricating system



Feb. 6, 1945.

E. yv. DAVIS CENTRALIZED LUBRICATING SYSTEM Filed Sept. 22, 1943 2 Sheets-Sheet l Feb. 6, 1945. w, DAV|5 2,368,808

CENTRALIZED LUBRICATING SYSTEM Fi led Sept. 22, 1945 2 Sheets-Sheet 2 J8 68 @002 or:

Patented Feb. 6, 1945 UNITED STATES PATENT OFFICE 2,368,808 l 1 CENTRALIZED LUBRICATING SYSTEM Ernest 'W. Davis, RiverFore'st, Ill. Application September 22, 1943, Serial No. 503,386 3, Claims. (o1.1s4 7) Y My invention relates to automatic, centralized, greasing systems in which a power driven pump automatically discharges grease at regularly recurring time intervals, into a grease line containihg metering devices which measure the amount of grease discharged into each bearing. The present invention relates more particularly to one specific type of a centralized greasing system, a type which is advantageous in many ways, but which has never been commercially successful, owing to a single characteristic defect in its operation, and it is a specific object of this invention to provide means for correcting this single defect. This characteristic defect, and also the means for correcting it, will be fully explained hereinafter, by reference to the accompanying drawings, in which: ,7 l

Figures 1 to 5, inclusive, are diagrammatic views of various stages in the operation of a, lu-

bricating system of the type described,'and illustrate the single characteristic defect mentioned; Figure 6 is a plan view of one of the pistons used in this lubricating system;

Figure 7 is an elevation of the complete lubricating system of this invention; 1

Figure 8 is an enlarged plan view of one of the measuring valves illustrated in Figure '7;-

Figure 9 is a greatly enlarged sectional elevation of the measuring'valve shown in Figure 8, the section being taken on the line 9, 9 in Figure 8;

. Figure 10 is a central se'ctional elevation of the pressure regulator-shown in Figure 7; and

Figure 11 is a fragmentary section through the 'linell,llinFigure9.

Lubricating systems of the particular class about to be described have a characteristic tendency to discharge inaccurate and abnormally excessive amountsof lubricant into, some of the bearings, unless provision is made for circumventing this difllculty. This objectionable performance is caused by a repeating action which 00- 'tions' in the pressures of thesprings34.

which supplies grease under pressure to a plurality of measuring valves [4, Hi,- and I8, each-of which supplies lubricant to a bearing (not shown) requiringlubrication. Each. measuring valve includes aicylirlder 20, containing a sliding piston 22, provided with a longitudinal groove 24, as shown in plan view in Figure 6. Referring again to Figure 1, each piston-carries an upper valve closure 26,;and a lower valve closure 28. The upper valve closure 26 forms a grease tight connection with the inlet'port 3D, and the lower valvev closure 28 forms a grease tight connection with the outlet port 32. The spring 34 urges the piston '22 upwardly, so that normally ,the upper valve ,closure 26 closes the inlet port 30 as shown in measuring valvelfiin Figure l. v V f When greasepressure 'isgraduallybuilt up in thegrease linel2, it will eventually force the valve closure 26 downwardly against the action of the spring 34; whereupon the greatly increased area of the piston 22, which is then exposed to the grease pressure, will cause the piston to shoot downwardly in a fraction of a second to, the position shownin measuring valve HIV in Figure 1, thereby expelling a measured quantity of grease aslillustrated .by the slug 36, which in an'actual installation would pass into a bearing. The pistons 22, the various measuring valves I4, 16, and I8, will pop down in this manner one.

at a time, because each time one of the pistons moves downwardly the slightest amount,,it causes a drop in the line pressure.- In a, system of this kind including a considerable number of measuring valves, simultaneous discharges sometimes ocour, in which two measuring valves discharge at the'same time, but ordinarily they discharge one at a time, in the manner described, and in a sequence determined in some degree by the varia- In the measuring valves shown in Figures: I to 5, it is assumed for purposes of analysis that the spring in measuring valve I61 is of average strength; that the spring in measuring valve I4 is of slightly less than average strength; and that the spring in measuringvalve I8 is of slightly more than average strength. Under these conditions the measuring valves tend to pop one at a time consecutively from leftto right,

Referring again to Figure 1, after measuring valve M has discharged its measured supply of grease, the valve closure 28'seats against the outlet port, and prevents further discharge. Then, if the, grease pressure is released in the grease line 12, the spring 1M moves the piston Z2 upwardly-so as to close the inlet port as shown in measuring valve lBin Figure 1. During this upward movement of the piston 22, the grease in the space above the piston 22 may flow. down through the groove 24 into the space below the piston 22, whereupon the measuring valve will. then be charged with grease and ready for the next shot.

The action just described is that which occurs when the grease line contains only a single measuring valve. When several such measuring valves are installed in a single grease line, objectionable discrepancies appear in their performance, in a manner which will now be described. Assuming that measuringvalve I4 has discharged grease in the manner illustrated in Figure l, and that measuring valvesl6 and .IB. have not yet discharged, then when measuring made smaller in order to decrease manufacturing cost, rather than for the purpose of improving performance. 7

In'the measuring valve of this invention, the reduction in discharge volume has'been carried far beyond any other grease measuring valve now in use, and although not obvious until explained, the result of this radical reduction in discharge capacity has completely eliminated the former inherent tendency to operate with repeating action. 7

Ordinarily, bearings are greased in the manner I "described at intervals usually ranging from four valve IBstarts to open, as shown in Figure 2,

the drop in pressure in the grease line l2,,per-

mits the piston 22 to 'rise momentarily, in measuring valve [4, as shown in Figure 2. Then, when 1 the pressure in the grease line l2 again rises, the

piston 22 of'measuring valve 14 will again seat in its lowest position, as shown in Figure 3. Meanwhile the piston 22 of measuring valve I 6 Will:

have seated in its lowest position, as shown in Figure 3, and in doing so will have discharged its measured 'quantity of grease as indicated by the slug 3,8. It will be observed that the volume orthe slug of grease 36 exceeds that of the slug 38. This superfluous excess is due to the re-. peating action of measuring valve [4, which has just been described.

After the piston 22 in measuring valve I6 seats in its lowest position, as shown in Figure 3, the

pressure in the grease line I2 will again build up until measuring valve l8 starts 'to discharge, as shown in Figure 4. The resulting drop in pressure inthe' grease line 12, will then permit the pistons 22, 22 of both measuring valve l4, and measuring valve I6, to rise momentarily, as shown in'Figure 4. Then, when the pistons 22, 22, of all three measuring valves have seated in their lowermost positions, as shown inFigure 5,

measuringvalve 18 will have discharged its required amount'ofgrease, as indicated by'the slug 40. In the meantime, measuring valve IE will have discharged a. slight excess, resulting from one repeating action, and measuring valve l4 will have discharged a greater excess, due to two'repeating actions, as shown in Figure 5 Thus it becomes obvious that in a lubricatingsystem such as the. onedescribed, the performance is unsatisfactory when a considerable number of measuring valves are connected in ,a single system.

From the foregoing description of the performance of this measuring valve, it is obvious that there is a characteristic defect in its performance and the correction of this defect is the specific object of this invention. This correction involves a radical change from the usual practice in grease lubrication, by the provision of measuring valves which dischargevery minute quantities of grease at each operation. In past lubricating practice it hasloeen considered desirable to inject a quantity of grease ateach lubrication that is equivalent in volume to at least the volumeof the lubricating filmbetween the bearing and the shaft, so that all the contaminated grease comprising the lubricating film will be ejected in advance of the-new, clean grease which displaces it. This procedure is generally recognized as good practiceand in the moderate shots'a day to one shot a week, depending on the conditions of service, but in the present inven- "tion the'frequency of lubrication is increased to grease into the grease line 44, at regularly re-' curring time intervals. Whenthepressure in the grease line 44 reaches a predetermined maximum value the grease pump 42 automatically stops pumping, and releases the pressure in the lubricant line 44. Several grease pumps of this class are disclosed in the prior art, including one disclosed in my copending application Serial Number-499,157, filed August 18, 1943.

A number of,measuring valves 46 are supplied with grease under pressure from the grease line Y44, and each measuring valve 46, discharges grease into one of the bearings 48, requiring lubrication. Each of the measuring valves 46, comprises a hollow. body portionv 50 (Figure. 9) provided with compression bushings 52 for attachmentto the grease line 44 The threaded portion 54 is adapted for connection with a bearing requiring lubrication. The cylindrical sleeve 56 is provided with an inlet opening 58, the edge of which provides a valve seat for they valve closure 60 carried by the valve stem 62. The valve stem 62'has a head 64,

against which the compression spring 66 applies a force for normally holding the valve 60 against the inlet opening 58. The lower end of the'valve stein 62 'is tapered to provide the valve closure 68, which is adapted to seal against the valve seat 10, formed by'the'outlet port 12. The slot 14 permits the flow of grease from the interior of the-sleeve 56 out through the discharge port 12,'until the valve-closure 68 contacts the valve seat 10. The upper part of the valve stem 62 is provided with a groovefl'fi, to,permit-'the passage of grease downwardly fpast the head 64. The screw cap "is provided with agasket for preventing leakage ofgrease. V

The pressure regulator 82 (Figure '7) comprises an air cylinder 84 connected with the compressed air supply tothe grease pump, by means of departures from this method which-haveape peard in practice, "the measuring" valves were the air tube 86. The air cylinder 84, 'contains'a piston 88 (FigurelO) connected with a grease plunger 90, having'a lappedfit in the grease cylinder92.

The operation of this lubricating system is as.

follows: When thereciprocating grease pump The use of a measuring; valve havingv such a 42 de1iversgrease to the grease line, the grease flows freelyaround each sleeve 56, of the 'measuring valves 46, so that the grease pressure is distributed to all' thefmeasuring valves 46. The pressure then builds up in [the greaseline .44, until .a pressure is. reached that is capable of valves, whereupon the grease pressure then acts measuring valve discharges, is very small, and

therefore, sufiicient pressure is maintained in the grease line 44 to hold each valve closure 68 seated on the valve seat 10,.against the action of the sprimg 65. a

. The amount of movement of the valve stem 62 determines the amount of lubricant discharged at each lubrication. This amount of movement may be difierent in different measuring valves, so that measuringvalves of difierent discharge capacities maybe provided for bearings having different lubricating requirements. If the sleeve small dischargecapacity ".tv'ill'of course require ,frequent' operation in order to provide adequate lubrication- The grease pump shown in Figure 7 ,may be adjusted to. operate at ya frequency-of -'from one to twenty operations. an hour, which "opening the valve 60 one of the measuring provides ample latitude 'for all ordinary lubricating requirements. I

Without further elaboration the foregoing will so fully explain my invention that others may,

by applying knowledge current at the time of, ap plication, readily adapt the same for use under va ying conditions of service. .Iclaim:f v

1. In a centralized lubricating system, a grease conduit; a high pressure reciprocating grease pump arranged to discharge greaseunder pres,

sure into said grease conduit; driving mechanism 56 is reduced in length, so as to reduce the distance between the inlet opening 58 and the valve seat '10, the amount of grease discharged will then be reduced, as will be readily understood.

The measuring valves shown in Figure 7 are not drawn in true proportion. To do so would involve unusual drafting difficulties, and therefore they are shown larger than their proportional size. The actual size of this measuring valve may be realized when it is considered that the screw thread 54, as shown in the enlarged view (Figure 9) is a one-eighth inch pipe thread. The actual maximum discharge capacity of this measuring valve is approximately .004 cubic inch, and by making the sleeve 56 a little shorter this capacity may be reduced to as little as .0005 cubic inch. During the discharge of such a minute quantity of grease from the grease line 44, the resilienc of the grease in the grease line is usually sufficient to maintain a pressure in the grease line high enough to hold the valve closure 88 on the valve seat 10, against the action of the spring 66, thereby preventing repeating action in the manner hereinbefore described.

In case the grease line 44 should be abnormally short, whereby the efiect of the resiliency of the grease contained therein might be insufiicient to maintain an operative pressure, then the pressure regulator 82 will assist in maintaining adequate pressure in the grease line at all times during the lubricating operation. The reciprocating grease pump 42 ordinarily pumps the grease with characteristic, intermittent discharges, and each time the flow. of grease is interrupted momentarily, there may be a momentary tendency towards repeating action in'the measuring valves. But the air. pressure acting on the air piston 88 forces the, plunger 90 downwardly in the grease cylinder 92, at each substantial drop in the grease pressure, thereby main taining the line pressure more nearly constant.

The relative areas of th grease plunger 90 and the air piston 88 is such that the maximum grease pressure is suflicient to t 90 against the action the piston 88.

raise the grease plunger of the air pressure above for actuating said pump, said driving mechanism being energized by a'supply. of fluid under pressure; means' for intermittently starting 'and stopping said driving mechanism at relativelyshort time intervals; means for intermittently releasing the grease pressure in saidgrease conduit," a

pressure regnlator connected with said grease conduit for regulatingthe pressure therein, said pressure regulator includingmeans actuated by said fluid pressure for displacing grease 'in said grease conduit incidentally with a predetermined drop of pressure therein; and a plurality of sequentially operative measuring valves for discharging grease in measured quantities into a plurality of bearings, said measuring valves receiving grease from said conduit, and each of said measuring valves comprising: a cylindrical displacement chamber having a grease inlet port and a grease outlet port, an inlet valve for said inletport, said inlet valve opening in the direction of grease flow,an outlet valve for said outlet port, said outlet valve closing in'the direction of grease flow, a connecting portion connecting said inlet'valve and said outlet valve, resilient means tending to hold said inlet valve closed, and tending to hold said outlet valve open, piston means reciprocable in said displacement chamber, said piston means being connected with said connecting portion and being movable therewith, and

said piston means incompletely sealing the passage of grease through said displacement cham-.

her, the transverse area of said displacement chamber being greater than the area of said out let port, and the area of said outlet port being greater than the area of said inlet port, and the displacement of said piston means being s0 minute that the drop in pressure in said grease conduit due to the discharge of said minute quantity of grease through one of said measuring valves, will be of such relatively smallvalue as to maintain an adequate pressure in said grease conduit, sufiicient to hold said outlet valve closed in another of said measuring valves, whereby repeating action of said measuring valves is prevented. 4

2. In a centralized lubricating system, a grease conduit; means for intermittently discharging grease into said grease conduit at relatively short time intervals; means .for intermittently releas ing the grease pressure in said grease conduit;

and a plurality of sequentially operative measur-- grease in measured quantities into a plurality of bearings, said' ing valves for discharging measuring valves receiving grease from said conduit, and each of said measuring valves comprising: a cylindrical displacement chamber having a greaseinlet port and a grease outlet port, an 4 t inlet valve for said inlet port, said inlet valve 1 opening in the direction of grease:flow, an outlet valve for said outlet port, said outlet valve closing 1 in the direction of grease fiow,-a connecting pore tion connecting said'inlet va1ve' and said outlet valve, resilient means tending to hold said .inlet valve closed, and tending to hold said outlet valve supplying ,lubricant' at above a predetermined open, piston means reciprocable'in said displaceproducing a drop invpressure to 'a' point below the 1 pressure necessary for holding said outlet valves closed against the action of said resilient means, 1 whereby repeating action in all of said measuring 1 valvesisprevented.

-3. In a lubricating system having means for j sagas I pressure for a 'short interval and relieving the pressure to substantially atmospheric pressure between the intervals of pressure application, a lubricant filledflconduit system receiving lubricant from said source, and aplurality of measure ing devices connected parallel to said conduit system, said measuring devices being of a type having a restricted b-y-pass displacement member determining the amount oflubrlcant discharged from the measuring'device and including a valve part for stopping discharge aftera 'measured charge of lubricant'has been displaced by the displacement member, each of said device's'having a lubricant discharge capacity so small relative to the volumetriccapacity of the conduit system that the discharge of the measured quantity of lubricant through the operationof one of said devices does not lower thespressure of the lubricant supplied to' anyone of the other devices connected to the conduit system below said predetermined-pressure, whereby undesired repeat-g v ing actic nof the measuringdevices is prevented;

ERNEST W. DAVIS. 

